4.3.0

• Added inactivity timeout (#263)
  This provides a separate timeout while waiting for the response or streaming the body. If no data is received for the response within the given number of milliseconds, the request fails similarly to the transfer timeout.
• Close idle connections if there are too many
  Requesting URLs from many hosts without reusing connections will otherwise result in resource exhaustion due to too many open files.
• Improved types for static analysis